Low Shrinkage Corrosion-Resistant Brass Alloy

ABSTRACT

A low shrinkage corrosion-resistant brass alloy contains 58 to 64 wt % of copper; 0.1 to 0.3 wt % of tin; less than 0.25 wt % of lead; 0.01 to 0.15 wt % of phosphorus; and more than 97.5 wt % of copper and zinc; zinc and unavoidable impurities; and more than 98 wt % of copper and zinc. It is to be noted that at least two of nickel, niobium, zirconium and aluminum is in an amount ranging from 0.01 to 0.4 wt %.

FIELD OF THE INVENTION

The present invention relates to a low shrinkage corrosion-resistantbrass alloy.

BACKGROUND OF THE INVENTION

Major components of brasses are copper, zinc and a small amount ofimpurities, wherein copper and zinc are usually present at a ratio ofabout 7:3 or 6:4. It is known that brasses contain lead (mainly rangingfrom 1 to 3 wt %) to improve the properties thereof by achieving thedesirable mechanical property at the industrial level, and thus thebecome important industrial materials which are widely applicable toproducts such as metallic devices or valves used in pipelines, faucetsand water supply/drainage systems.

However, as the awareness of environmental protection increases and theimpacts of heavy metals on human health and issues like environmentalpollutions become major focuses, it is a tendency to restrict the usageof lead-containing alloys. Various countries such as Japan, the UnitedStates of America, etc, have sequentially amend relevant regulations,putting intensive efforts to lower lead contents in the environment byparticularly demanding that no molten lead shall leak from thelead-containing alloy materials used in products such as householdelectronic appliances, automobiles and water systems to drinking waterand lead contamination shall be avoided during processing. Thus, thereexists an urgent need in the industry to develop a lead-free brassmaterial, and find an alloy formulation that can substitute forlead-containing brasses while having desirable properties like thecasting property, machinability, corrosion resistance and mechanicalproperties.

Conventionally, bismuth (Bi) is added in brass alloys as a majorcomponent to replace lead so as to have casting, machining polishing,and plating process efficiently. However, the high bismuth content islikely to cause defects like cracks and slag inclusions, and bismuth hasradioactivity which is harmful to human.

The present invention has arisen to mitigate and/or obviate theafore-described disadvantages.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a lowshrinkage corrosion-resistant brass alloy which is capable of overcomingthe shortcomings of the conventional brass alloy.

To obtain the above objectives, a low shrinkage corrosion-resistantbrass alloy contains: contains 58 to 64 wt % of copper; 0.1 to 0.3 wt %of tin; less than 0.25 wt % of lead; 0.01 to 0.15 wt % of phosphorus;and more than 97.5 wt % of copper and zinc; zinc and unavoidableimpurities; and more than 98 wt % of copper and zinc.

It is to be noted that at least two of nickel, niobium, zirconium andaluminum is in an amount ranging from 0.01 to 0.4 wt %.

In a preferred embodiment, the niobium is in an amount ranging from 0.07to 0.15 wt %.

In a preferred embodiment, the nickel is in an amount ranging from 0.07to 0.15 wt %.

In a preferred embodiment, the lead is in an amount ranging from 0.08 to0.2 wt %.

In a preferred embodiment, the tin is in an amount ranging from 0.15 to0.25 wt %.

In a preferred embodiment, the phosphorus is in an amount ranging from0.08 to 0.15 wt %.

In a preferred embodiment, the zirconium is in an amount ranging from0.07 to 0.15 wt %.

In a preferred embodiment, wherein the aluminum is in an amount rangingfrom 0.07 to 0.25 wt %.

Thereby, the low shrinkage corrosion-resistant brass alloy of thepresent invention has the following advantages:

1. The niobium is added to the low shrinkage corrosion-resistant brassalloy so as to enhance the fluidity of the brass and to lower shrinkageof the brass in the casting process. In addition, the corrosionresistance of the brass is increased.

2. By adding less lead, insoluble solid solution forms in the copper andevenly disperses between two phases, thereby enhancing machinability.

3. The low shrinkage corrosion-resistant brass alloy increasesmechanical property and the corrosion resistance of the brass andenhances strength, hardness, and machinability of the alloy material,thus improving machining performance of the brass.

The foregoing, as well as additional objects, features and advantages ofthe invention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a 64 brass without adding any element and a metallographicstructural distribution of a low shrinkage corrosion-resistant brassalloy with niobium and a low shrinkage corrosion-resistant brass alloywith 0.01-0.15 wt % of phosphorus according to the present invention.

FIG. 2 shows a specimen of the low shrinkage corrosion-resistant brassalloy with the niobium and a comparison of stereoscopic microscopephotos of different chip shapes after a machining text according to thepresent invention.

FIG. 3A shows a structural distribution of a low shrinkagecorrosion-resistant brass alloy according to the present invention.

FIG. 3B shows a structural distribution of a lead-free bismuth brass inthe comparative example 1.

FIG. 3C shows a structural distribution of a H-59 lead brass.

FIG. 4A shows a metallographic structural distribution after performinga test of dezincification corrosion resistance on a specimen of alead-free bismuth brass.

FIG. 4B shows a metallographic structural distribution after performinga test of dezincification corrosion resistance on a specimen of the H-59lead brass.

FIG. 4C shows a metallographic structural distribution after performinga test of dezincification corrosion resistance on a specimen of the lowshrinkage corrosion-resistant brass alloy of the present invention.

FIG. 5 is a design diagram of a mold used in a test example 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Compositions of a low shrinkage corrosion-resistant brass alloyaccording to the present invention is on the basis of total alloy weightand are presented are calculated by weight percent (wt %). It is to benoted that when

The present inventors found that when a high tin content (i.e., morethan 2 wt %) is added to the brass alloy conventionally, at the microlevel, a γ phase will generate to corrode workpiece or increasehardness, thus machining the workpiece difficulty.

The low shrinkage corrosion-resistant brass alloy of the presentinvention has added niobium, so in the high-temperature melting process,the niobium is covered in the brass pipe so that intermediate of theniobium and the brass is dissolved into the brass.

FIG. 1 shows a 64 brass without adding any element and a metallographicstructural distribution of a low shrinkage corrosion-resistant brassalloy with niobium and a low shrinkage corrosion-resistant brass alloywith 0.01-0.15 wt % of phosphorus, wherein (a) represents the 64 brasswithout any added element, (b) denotes the low shrinkagecorrosion-resistant brass alloy with the niobium, and (c) manes the lowshrinkage corrosion-resistant brass alloy with 0.01-0.15 wt % ofphosphorus. In this embodiment, the low shrinkage corrosion-resistantbrass alloy comprises 0.07-0.12 wt % of niobium, 0.08-0.15 wt % ofphosphorus, and 0.1-0.3 wt % of tin.

From (b) of FIG. 1, we can learn that after adding niobium to the lowshrinkage corrosion-resistant brass alloy, a shrinkage of the brassalloy is reduced, a fluidity is enhanced, and a corrosion-resistant αphase is stabilized in the brass alloy, thereby increasingdezincification resistance.

It can be learned from (c) of FIG. 1, after adding 0.08-0.15 wt % ofphosphorus to the low shrinkage corrosion-resistant brass alloy, thefluidity in the casting process is increased, and thecorrosion-resistant α phase is stabilized in the brass alloy. But ifadding excessive tin to the low shrinkage corrosion-resistant brassalloy, γ brittle phase forms in the brass to deteriorate corrosionresistance and mechanical properties. Accordingly, a range of tin iswithin 0.1 wt % to 0.3 wt %. Preferably, the tin is in an amount rangingfrom 0.15 to 0.25 wt %.

Furthermore, the low shrinkage corrosion-resistant brass alloy with theniobium comprises less than 0.25% of lead calculated based on percentageby weight. Since the lead does not melt in the brass, so themachinability of the copper is enhanced.

Because excessive lead will pollute the environment and harm human, thetin is limited in an amount ranging from 0.08 to 0.25 wt %.

Generally, the chips broking from the brass includes rolled chips,C-shaped short chips, and flakes chips, wherein the rolled chips attachon the blade easily to lower machinability, the C-shaped short chipsgenerate from a better machining process, and the flakes chips resultsfrom a best machining process.

FIG. 2 shows a specimen of the low shrinkage corrosion-resistant brassalloy with the niobium and a comparison of stereoscopic microscopephotos of different chip shapes after a machining text, wherein (a)represents a specimen of the rolled chips of the low shrinkagecorrosion-resistant brass alloy with niobium and 0.08 to 0.15 wt % oflead content, (b) denotes a specimen of the C-shaped short chips of thelow shrinkage corrosion-resistant brass alloy with niobium and 0.08 to0.15 wt % of lead content, (c) manes a specimen of the flake chips ofthe low shrinkage corrosion-resistant brass alloy with niobium and morethan 2 wt % of lead content, (d) implies a specimen of the flake chipsof the low shrinkage corrosion-resistant brass alloy with niobium andless than 2 wt % of lead content.

The niobium can avoid workpiece material from crack and hasmachinability like lead brass (such as H-59 lead brass). Thereby, thelow shrinkage corrosion-resistant brass alloy of the present inventionlowers lead content and production cost and enhances machinability.

Moreover, according to the low shrinkage corrosion-resistant brass alloyof the present invention, the lead content of the alloy can be loweredto a range less than 0.2 wt %, so as to conform to the stipulatedinternational requirement for the leads contents in water pipelines.Hence, the low shrinkage corrosion-resistant brass alloy according tothe present invention is applicable to applications to manufacturing offaucets and laboratory components, water pipelines and water supplysystems.

The present invention is illustrated in details by the exemplaryexamples below. Test example 1:

Test Example 1

Under the same producing and operating conditions, the low shrinkagecorrosion-resistant brass alloy (examples 2 to 4) of the presentinvention, lead-free bismuth brass alloy (comparative examples 1 to 2),and H-59 lead brass (comparative examples 3 and 4) were used asmaterials to produce the same product. The processing characteristics ofeach of the alloys and the non-defectiveness in production at each stagewere compared, wherein the non-defectiveness is defined as follows:

non-defectiveness in production=the number of non-defective products/thetotal number of products×100%

The non-defectiveness in production reflects the qualitative stabilityof the production. High qualitative stability ensures normal production.

TABLE 1 Statistical data of the products lead-free bismuth brass H-59lead brass compar- compar- compar- compar- low shrinkagecorrosion-resistant brass alloy ative ative ative ative embodi- embod-embod- embod- embod- category example 1 example 2 example 3 example 4ment 1 iment 2 iment 3 iment 4 iment 5 measured Cu 62.48 62.57 61.5 61.159.96 64.35 62.13 61.09 60.49 content (%) measured Bi 0.762 0.549 0.01190.0089 0.0026 0.0037 0.0061 0.0054 0.0044 content (%) measured Al 0.5130.556 0.607 0.589 0.009 0.007 0.03 0.012 0.005 content (%) measured Pb0.0075 0.0042 1.47 1.54 0.09 0.12 0.11 0.12 0.08 content (%) measured Mg0.0014 0.0049 0.0119 0.0089 0.003 0.004 0.002 0.003 0.002 content (%)measured Zr 0.0011 0.0023 0.0002 0.0001 0.004 0.003 0.003 0.002 0.14content (%) measured Ni 0.210 0.238 0.128 0.147 0.056 0.053 0.048 0.1240.053 content (%) measured Sn 0.364 0.285 0.287 0.342 0.200 0.183 0.2200.211 0.198 content (%) measured Sb 0.0028 0.0094 0.0092 0..0010 0.0050.007 0.06 0.003 0.005 content (%) measured Nb 0.00001 0.00002 0.000030.00003 0.09 0.12 0.2 0.003 0.002 content (%) measured P 0.0003 0.00020.0003 0.0002 0.09 0.10 0.12 0.10 0.12 content (%) non-defectiveness 71%78% 96% 96.2%   97.4    98.2%   98.8%   99.3%   97.8    in castingnon-defectiveness 84% 82% 99% 99% 98% 99% 99% 98% 98% in mechanicalprocessing non-defectiveness 89% 88% 92% 94% 95% 94% 95% 94% 95% inpolishing processing Total 53.1%   56.3%   87.4%   88.4%   90.7%  91.4%   93% 91.5%   91.1%   non-defectiveness

As shown in Table 1, when lead-free bismuth brass is used as a materialfor product casting, more casting defects are found in the obtainedcasting part. Thus, the total non-defectiveness in production is lowerthan 60%. The higher the bismuth content, the lower thenon-defectiveness. The major defects observed in the casting part inwhich lead-free bismuth brass is used as material are voids, slaginclusions, cracks, misrun and shrinkage. The defective products withthe above defects comprise 71% of the total number of defectiveproducts. Specifically, the fluidity of the molten copper liquid of thelead-free bismuth brass is low and the filling of the mold is poor, suchthat the casting part is prone to misrun. Cracking is likely to occur inthe casting part, and some minor cracks are not found until the finalpolishing step. Slag inclusions and voids are likely to occur in thecasting part. Further, the machinability of lead-free bismuth brass ispoor, such that problems like vibration and adhesion are likely tooccur, thereby causing low non-defectiveness during subsequentmechanical processing.

Moreover, when the low shrinkage corrosion-resistant brass alloy of thepresent invention is used as a raw material in the test group, thenon-defectiveness is the best (i.e., higher than 90%), and the materialfluidity of the low lead brass is close to that of the conventionalC85710 lead brass. After performing optimization of the casting art, anequiaxed dendritic crystal phase structure with low occurrence ofembrittlement is obtained after the casting part solidifies. Whileensuring the machinability, the above structure ensures that defectslike cracking is not prone to occur, so that the entire material cansuffice the production requirements. Among them, high phosphorus contentis likely to cause casting defects in brass alloys, and lowernon-defectiveness.

Test Example 2

Specimens of brass materials of the third embodiment, the comparativeexample 1, and the comparative example 4 were placed under ametallographic microscope to examine the structural distribution of thematerial. The results magnified at 100-fold is shown in FIG. 3A to 3C.

The measured values of the ingredients of the low shrinkagecorrosion-resistant brass alloy in the third embodiment are Cu: 62.13 wt%, Bi: 0.0061 wt %, Al: 0.03 wt %, Pb: 0.11 wt %, Mg: 0.002 wt %, Zr0.003 wt %, Ni: 0.048 wt %, Sn: 0.220 wt %, Sb: 0.06 wt %, Nb: 0.2 wt %,P: 0.12 wt %. The structural distribution of the low shrinkagecorrosion-resistant brass alloy of the third embodiment is shown in FIG.3A, wherein an round crystal phase structure is shown, and some grainsare finely round, so the material is prone to chip breaking and canprovide good machinability. Further, the round crystal phase structurehas low occurrence of embrittlement, thereby not being likely to havedefects like cracks.

The measured values of the ingredients of the lead-free bismuth brass inthe comparative example 1 are Cu: 62.48 wt %, Bi: 0.762 wt %, Al: 0.513wt %, Pb: 0.0075 wt %, Mn: 0.0047 wt %, Ni: 0.210 wt %, Sn: 0.364 wt %,and Sb: 0.0028 wt %.

FIG. 3B shows a structural distribution of the lead-free bismuth brassin the comparative example 1, wherein when bismuth content is high, moreheterogeneous nucleation sites are formed and nucleation rates are high;and the higher the undercooling of the composition of a phase, thegrains formed are mainly dendritic and rarely massive crystals. Hence,bismuth segregates on the grain boundary and generate continuously flakybismuth, so that the mechanical strength of the material breaks down andthe hot shortness and cold shortness are increased, thereby causing thematerial to crack.

The measured values of the ingredients of the H-59 lead brass in thecomparative example 4 were Cu: 61.1 wt %, Al: 0.589, Bi: 0.0089 wt %,Pb: 1.54 wt %, Mn: 0.0009 wt %, Ni: 0.147 wt %, Sn: 0.342 wt %, and Sb:0.0010 wt %.

FIG. 3C shows a structural distribution of the H-59 lead brass, whereina phase of the alloy is round-shaped and has good toughness, and thus itis not likely to have defects like cracks.

Test Example 3

A test was performed according to the standards set forth in NSF61-2007a SPAC for the allowable precipitation amounts of metals inproducts, to examine the precipitation amounts of the metals of thebrass alloys in aqueous environments. Results are shown in Table 2.

As shown in Table 2, various metal precipitation amounts of the lowshrinkage corrosion-resistant brass alloy of the present invention arelower than the upper limits of the standard values, and therefore, thelow shrinkage corrosion-resistant brass alloy of the present inventionconforms to NSF 61-2007a SPAC.

TABLE 2 Precipitation amounts of metals in the products comparativeUpper limits example 3 of standard comparative (after a lead embodi-Element values (ug/L) example 3 stripping treament) ment 2 lead (Pb) 5.019.173 0.462 0.179 bismuth (Bi) 50.0 0.011 0.006 0.005 stibium (Sb) 0.60.008 0.006 0.003

Further, the low shrinkage corrosion-resistant brass alloy of thepresent invention clearly had a lower precipitation amount of the heavymetal, lead, than that of the H-59 lead brass. Thus, the low shrinkagecorrosion-resistant brass alloy of the present invention conforms to thestandards set forth in NSF 61-2007a SPAC and is more environmentallyfriendly, and more beneficial to human health.

Test Example 4

A dezincification test was performed on the brass alloys in the thirdembodiment and comparative example 2 to examine the corrosion resistanceof brass. The dezincification test was performed according to thestandards set forth in Australian AS2345-2006 “Anti-dezincification ofcopper alloys”. Before a corrosion experiment was performed, a novolakresin was used to make the exposed area of each of the brasses to be 100mm², the specimens were ground flat using a 600# metallographic abrasivepaper following by washing using distilled water, and the specimens werebaked dry The test solution was 1% CuCl2 solution prepared before use,and the test temperature was 75±2° C. The specimens and the CuCl₂solution were placed in a temperature-controlled water bath to react for24±0.5 hours, and the specimens were removed from the water bath and cutalong the vertical direction. The cross-sections of the specimens werepolished, and then the depths of corrosion thereof were measured andobserved under a digital metallographic microscope.

FIG. 4A shows the metallographic structural distribution afterperforming a test of dezincification corrosion resistance on thespecimen of a lead-free bismuth brass, wherein the average dezincifieddepth of the lead-free bismuth brass (Bi: 0.556%) in comparative example2 was 298.45 μm; and FIG. 4B shows the metallographic structuraldistribution after performing a test of dezincification corrosionresistance on the specimen of the H-59 lead brass, wherein the averagedezincified depth of the H-59 lead brass in comparative example 3 was204.64 μm. FIG. 4C shows the metallographic structural distributionafter performing a test of dezincification corrosion resistance on thespecimen of the low shrinkage corrosion-resistant brass alloy of thepresent invention, wherein the average dezincified depth of the H-59lead brass in the second embodiment was 68.62 μm.

The above results proved that the low shrinkage corrosion-resistantbrass alloy of the present invention had better dezincificationcorrosion resistance.

Test Example 5

A mechanical property test was performed on the brass alloys accordingto the standards set forth in IS06998-1998 “Tensile experiments onmetallic materials at room temperature”. Results are shown in Table 3.

As shown in Table 3, the tensile strength of the low shrinkagecorrosion-resistant brass alloy of the present invention is higher thanthe H-59 lead brass in the fourth embodiment and the lead-free bismuthbrass alloy in the comparative example 1, and the elongation of the lowshrinkage corrosion-resistant brass alloy of the present invention issimilar to the H-59 lead brass in the fourth embodiment. This means thatthe low shrinkage corrosion-resistant brass alloy of the presentinvention has better mechanical property than the H-59 lead brass andthe lead-free bismuth brass alloy.

TABLE 3 Results of the mechanical property test mechanical property Typeof tensile strength (Mpa) elongation (%) material 1 2 3 4 5 average 1 23 4 5 average embodiment 1 429 434 425 447 420 431 19.5 21.2 22.1 20.917.1 20.16 comparative 372 370 385 365 370 372.3 20.1 19 24 26.5 24.522.8 example 4 comparative 422 402 408 418 408 411.7 11.6 12 14 12 13.212.6 example 1

Test Example 6

A shrinkage test was performed on the brass alloys in the embodimentsand comparative examples to examine the solidification shrinkage valuesof brass. A measuring method of the shrinkage is listed as follows:

pouring 43 grams of high-temperature brass liquid into a mold andobserving casting property, wherein because atom shrinks and fills intoa casting head of the mold in a cooling process, so a volume is 5×1×1cm³, and the shrinkage is estimated. FIG. 5 is a design diagram of themold used in this text.

A plastic head dropper is applied to hold pure water, and 0.05 ml ofwater drop is dropped into a shrinkage hole, wherein a dropping amountof the pure water is calculated and is exchanged to a shrink percentageaccording to the following formula:

Shrinkage=dropped water volume/a volume of casting head×100%

TABLE 5 Comparison of the shrinkage lead-free bismuth brass H-59 leadbrass low shrinkage corrosion-resistant brass comparative comparativecomparative comparative alloy Item example 1 example 2 example 3 example4 embodiment 1 embodiment 2 embodiment 3 No. 1 4.38% 5.58% 8.06% 7.36%1.02%   0%   0% No. 2 4.34% 5.44% 8.26% 7.26% 1.00%   0%   0% No. 34.37% 5.35% 8.36% 7.86% 1.03% 0.05% 0.05% No. 4 4.38% 5.62% 8.26% 7.76%1.02% 0.05%   0% No. 5 4.32% 5.42% 8.16% 7.66% 1.02% 0.05% 0.05% Average4.358%  5.482%  8.22% 7.58% 1.018%  0.03% 0.02%

As shown in Table 4, the solidification shrinkage of brass alloy of thelow shrinkage corrosion-resistant brass alloy of the present inventionis lower than lead-free bismuth brass in the comparative examples 1, 2and the H-59 lead brass in the comparative examples 3 and 4. This meansthat the low shrinkage corrosion-resistant brass alloy of the presentinvention improves the casting property of the alloy material.

While the preferred embodiments of the invention have been set forth forthe purpose of disclosure, modifications of the disclosed embodiments ofthe invention as well as other embodiments thereof may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments which do not depart from the spirit and scope ofthe invention.

What is claimed is:
 1. A low shrinkage corrosion-resistant brass alloycomprising: 58 to 64 wt % of copper; 0.1 to 0.3 wt % of tin; less than0.25 wt % of lead; 0.01 to 0.15 wt % of phosphorus; and more than 97.5wt % of copper and zinc, wherein at least two of nickel, niobium,zirconium and aluminum is in an amount ranging from 0.01 to 0.4 wt %;zinc and unavoidable impurities; and more than 98 wt % of copper andzinc.
 2. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 1, wherein the niobium is in an amount ranging from 0.07 to 0.15wt %.
 3. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 2, wherein the nickel is in an amount ranging from 0.07 to 0.15 wt%.
 4. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 3, wherein the lead is in an amount ranging from 0.08 to 0.2 wt %.5. The low shrinkage corrosion-resistant brass alloy as claimed in claim4, wherein the tin is in an amount ranging from 0.15 to 0.25 wt %. 6.The low shrinkage corrosion-resistant brass alloy as claimed in claim 5,wherein the phosphorus is in an amount ranging from 0.08 to 0.15 wt %.7. The low shrinkage corrosion-resistant brass alloy as claimed in claim6, wherein the zirconium is in an amount ranging from 0.07 to 0.15 wt %.8. The low shrinkage corrosion-resistant brass alloy as claimed in claim7, wherein the aluminum is in an amount ranging from 0.07 to 0.25 wt %.9. The low shrinkage corrosion-resistant brass alloy as claimed in claim1, wherein the nickel is in an amount ranging from 0.07 to 0.15 wt %.10. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 1, wherein the lead is in an amount ranging from 0.08 to 0.2 wt %.11. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 1, wherein the tin is in an amount ranging from 0.15 to 0.25 wt %.12. The low shrinkage corrosion-resistant brass alloy as claimed inclaim 1, wherein the phosphorus is in an amount ranging from 0.08 to0.15 wt %.
 13. The low shrinkage corrosion-resistant brass alloy asclaimed in claim 1, wherein the zirconium is in an amount ranging from0.07 to 0.15 wt %.
 14. The low shrinkage corrosion-resistant brass alloyas claimed in claim 1, wherein the aluminum is in an amount ranging from0.07 to 0.25 wt %.
 15. The low shrinkage corrosion-resistant brass alloyas claimed in claim 1, wherein at least two of nickel, niobium,zirconium and aluminum is in an amount ranging from 0.07 to 0.25 wt %.